/Engine/Source/Editor/UnrealEd/Public/SCommonEditorViewportToolbarBase.h
Build the screen percentage menu.
static void ConstructScreenPercentageMenu ( [FMenuBuilder](API\Runtime\Slate\Framework\MultiBox\FMenuBuilder) & MenuBuilder, class [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) * ViewportClient )